Conductivity additive for liquid hydrocarbons

ABSTRACT

A COMPOSITION CONSISTING ESSENTIALLY OF A TRIVALENT CHROMIUM SALT OF AN ORGANIC PHOSPHATE, A NITROGEN CONTAINING COPOLYMER AND AN AMINE NEUTRALIZED ALKYL PHOSPHATE INCREASES THE CONDUCTIVITY OF LIQUID HYDROCARBONS AND PREVENTS ACCUMULATION OF STATIC CHARGE IN HYDROCARBON FUELS AND SOLVENTS.

United States Patent Int. Cl. C101 1/26 US. C]. 44-62 4 Claims ABSTRACTOF THE DISCLOSURE A composition consisting essentially of a trivalentchromium salt of an organic phosphate, a nitrogen containing copolymerand an amine neutralized alkyl phosphate increases the conductivity ofliquid hydrocarbons and prevents accumulation of static charge inhydrocarbon fuels and solvents.

BACKGROUND OF THE INVENTION (1) Field of the invention This inventionrelates to an additive composition for liquid hydrocarbons, saidadditive consisting essentially of a trivalent chromium salt of anorganic phosphate, a nitrogen containing copolymer and an amineneutralized alkyl phosphate. This invention also relates to hydrocarbonliquid containing this additive composition.

(2) Descrption of the prior art Hydrocarbon liquids, both aliphatic andaromatic, distillate fuels and jet fuels and tend to accumulate apotentially hazardous electrostatic charge. A number of explosions andfires have occurred in recent years during the bulk handling andtransporting of gasolines, kerosene, jet fuels, fuel oils, andhydrocarbon solvents having boiling points between about 70 F. and 700F. These explosions have been attributed to the accumulation andsubsequent discharge of static electricity in systems involved. Somehandling conditions which contribute to the rapid generation ofdangerous charge levels are rapid flow of fuel through pipelines andhoses, splash filling of receiving vessels, such as storage tanks andseagoing tankers, and refueling of jet aircraft.

Various additives have been proposed to minimize the accumulation ofstatic electricity by increasing the conductivity of the hydrocarbonsolvent or fuel. These additives should be effective in smallconcentrations and have no adverse effects on the hydrocarbon products,especially jet fuels, where stringent specifications have to be met.

A number of metal salts of carboxylic acids, as shown in US. Patent No.3,012,969, and organic phosphate salt compositions, as shown in US.Patent No. 3,256,073, are useful in increasing the conductivity ofvolatile solvents and fuel oils. Although these metal salts increase theconductivity appreciably, their effectiveness tends to be short-lived, asubstantial portion being lost on storage.

In order to avoid this loss, it was proposed in US. Patent No. 3,013,868to mix a polymer with a chromium carboxylate. The polymer, preferably anitrogen containing acrylate or methacrylate copolymer, prolonged theconductivity level of the chromium carboxylates.

The conductivity level of some chromium salts of alkyl phophates wasalso found to be prolonged by the addition of nitrogen containingcopolymers. However, the advantage obtained by incorporating thecopolymer is ofiset by the fact that the salt-copolymer mixtures formgels, and thus can not be readily put to practical use. I have now foundthat a conductivity additive consisting of a chromium salt of an alkylphosphate and a nitrogen containing copolymer can be rendered liquid andmaintained in the liquid state while still retaining a high conductivity3,758,283 Patented Sept. 11, 1973 level, by incorporating an amineneutralized alkyl acid phosphate.

SUMMARY OF THE INVENTION In summary, this invention is directed to acomposition for increasing the conductivity of hydrocarbon liquidsconsisting of essentially of (1) one part by weight of a trivalentchromium salt of (a) an alkyl phosphate, said salt having the formulawherein R and R can be the same or different and R is alkyl of 1 to 1-6carbon atoms, alkylphenyl wherein the alkyl contains 1 to 1-6 carbonatoms, or phenyl, and

R is alkyl of 3 to 16 carbon atoms, alkylphenyl wherein the alkylcontains 1 to 16 carbon atoms, or phenyl; or

(b) a mixture of (i) 60 to 40 mol percent of a monohydrocarbondihydrogen phosphate, and

(ii) 40 to 60 mol percent of a dihydrocarbon monohydrogen phosphate,

wherein the hydrogen is alkyl of 4 to 16 carbon atoms, alkylphenyl thealkyl contains 1 to 16 carbon atoms, or phenyl (2) from .5 to 1 part byweight of an oil soluble copolymer wherein (a) one of the monomers isamine-free;

(b) one of the monomers contains from 8 to 18 carbon atoms in analiphatic hydrocarbon chain which is not part of the polymer chain;

(c) one of the monomers contains a basic amino nitrogen which is notitself part of the polymer chain; and

(d) each of the monomers, prior to polymerization, contains acarbon-carbon double bond capable of participation in free radicalinitiated addition copolymerization;

said copolymer containing from 0.1 to 3.5 weight percent of basic aminonitrogen; and

(3) from .5 to 16 parts by weight of an oil soluble salt (a) a 2 to 24carbon atom monoamine selected from among (i) tertiary alkyl primaryamines;

(ii) secondary amines having 2 mono-valent satuarted hydrocarbon radicalsubstituents; and

(iii) tertiary amines having 3 mono-valent sat-urated hydrocarbonradical substituents; and

(b) mixed monoalkyl acid phosphates and dialkyl acid phosphates whereinthe alkyl groups contain 8 to 18 carbon atoms.

This invention is further directed to concentrated solutions of theabove compositions in liquid hydrocarbonmiscible solvents and to theabove compositions in liquid hydrocarbons.

The composition of this invention are effective in raising theconductivity level of a hydrocarbon liquid, such as jet fuel or fueloil, and maintains a substantial portion of of its initial level ofeffectiveness in the liquid hydrocarbon during storage. Anotherparticular advantage of the compositions of this invention is that thecomponents remain in the oil phase during storage of the fuel, even inthe presence of small amounts of water; thereby retaining theireffectiveness. Moreover the compositions of this invention minimizesludge formation and enhance thermal stability of fuel oils.

DESCRIPTION OF THE INVENTION As stated above, this invention is directedto an additive composition for liquid hydrocarbons consistingessentially of a trivalent chromium salt of an organic phosphate, anitrogen containing copolymer, and an amine neutralized alkyl phosphate.The three components and their relative concentrations in thecompositions as well as their method of preparation are described below.

(1) Components of the additive compositions (A) Chromium phosphate.Thephosphate salts of chromium useful in this invention are the trivalentchromium salts of alkyl phosphates having the formula wherein R and Rcan be the same or different and R is alkyl of l to 16 carbon atoms,alkylphenyl wherein the alkyl contains 1 to 16 carbon atoms, or phenyl,and R is alkyl of 3 to 16 carbon atoms, alkylphenyl wherein the alkylcontains 1 to 16 carbon atoms, or phenyl; and the trivalent chromiumsalts of mixtures of 60 to 40 mol percent of a monohydrocarbondihydrogen phosphate and 40 to 60 mol percent dihydrocarbon monohydrogenphosphate wherein the hydrocarbon is alkyl of 4 to 16 carbon atoms,alkylphenyl wherein the alkyl contains 1 to 16 carbon atoms or phenyl.

Representative of suitabe chromium organic phosphates are the Cr(III)salts of di-substituted monohydrogen phosphates such as di-isooctylphosphate; di-Z-ethylhexyl phosphate; di-decyl phosphate; di-dodecylphosphate; di-tridecyl phosphate; di-hexadecyl phosphate; diphenylphosphate; di-p-ethylphenyl phosphate; di-p-nonylphenyl phosphate; di phexadecylphenyl phosphate; methyl isooctyl phosphate; ethyl isopropylphosphate; ethyl isooctyl phosphate; methyl-Z-ethylhexyl phosphate;methyl phenyl phosphate; ethyl n-octyl phosphate; ethyl Z-ethylhexylphosphate; methyl p-ethylphenyl phosphate; and methyl hexadecylphosphate; and the Cr(III) salts of mixed, substituted, acid phosphateswherein the substituents can be for example isooctyl, n-octyl,Z-ethylhexyl, dodecyl, tridecyl, hexadecyl, phenyl, p-ethylphenyl andpnonylphenyl.

Preferred chromium phosphates are those of Formula 1 above wherein R andR are alkyl and most preferred are those salts wherein R and R arebranched chain primary alkyls of 8 to 16 carbon atoms.

The chromium tri-phosphate salts can be conveniently prepared forexample by heating one mole of a salt of trivalent chromium, such as thetriacetate, tripropionate, or tributyrate salt, in a hydrocarbonsolvent, such as toluene or benzene, with 3 moles of the desiredhydrocarbon phosphate at reflux. The by-product acid, for exampleacetic, propionic or butyric, is distilled ofi, and the product chromiumtriphosphate salt is isolated from the reaction mass by distillation ofthe solvent.

The chromium salts can also be obtained by reaction of chromium chloridewith the appropriate phosphate as illustrated hereinafter in theexamples.

(B) Nitrogen-containing polymers-The polymers suitable for use in thepresent invention are oil-soluble copolymers derived from at least twodifferent polymerizable compounds, one of which must be amine-free, oneof which must contain from 8 to about 18 carbon atoms in an aliphatichydrocarbon chain which in the polymer is not part of the main polymerchain, (thereby providing an oleophilic structure) and one of which mustcontain a basic amino nitrogen structure, also not a part of the mainpolymer chain. The copolymers must contain at least 0.1% but not morethan 35%, by weight of basic amino nitrogen, and preferably between 0.2%and 3.0%. The polymer need not be derived from only two differentpolymerizable compounds as illustrated above but can also contain one ormore additional polymerizable compounds that do not by themselves formoil-soluble polymers. The latter is true providing the proportions arerestricted to insure that (a) the polymers have the requisite oilsolubility and(b) no substantial change occurs in the valuableproperties of these polymers as sludge inhibitors and dispersants. Abasic requirement is that the copolymer formed must have at least alimited solubility in the hydrocarbon liquid, i.e., at least 0.001% byweight. The term oil-soluble is used herein to denote a solubility of atleast 0.001%, by Weight, in the liquid hydrocarbon. It is alsopreferable that the copolymer have an inherent viscosity of between 0.1and 3.0 as determined at 0.1% weight-volume concentration in benzene at25 C.

As the oleophilic components of copolymers useful in the preparation ofthe compositions of this invention there can be employed polymerizableesters, amides, ethers, and hydrocarbons characterized by the presenceof at least 8 carbon atoms, preferably with 6 or more in a straightchain, and at least one carbon-carbon double bond capable ofparticipation in free radical initiated addition copolymerizationreactions. Examples of oleophilic components suitable for use are:saturated and unsaturated longchain esters of unsaturated carboxylicacids such as 2- ethylhexyl, acrylate, decyl acrylate,3,5,5-trimethylhexyl methacrylate, 9-octa-decenyl methacrylate;unsaturated esters of long-chain carboxylic acids such as vinylstearate; long-chain esters of vinylene dicarboxylic acids such asmethyl lauryl fumarate; N-long-chain hydrocarbon substituted amides ofunsaturated acids such as N-octadecyl acrylamide; and long-chainmonoolefins such as the alkyl or acyl substituted styrenes, e.g.,dodecylstyrene. Obviously, these components can be employed alone or invarious combinations and, in general, make up the majority of thepolymeric additive in order to insure proper oleophilic chanacter. Thetechnical lauryl methacrylate obtained from the commercial mixture oflong-chain alcoh'ols in the C to C range derived from coconut oil is anespecially useful oleophilic component of the copolymer but the group ofacrylic and alkacrylic esters of aliphatic alcohols of at least 8carbons also are, in general, Well suited as the oleophilic component ofthe copolymer.

The basic amino nitrogen-containing component can be introduced throughthe use of appropriate copolymerizable monomers containing primary,secondary or tertiary amino nitrogen that is attached ultimately to thechain of the polymer as part of an extralinear substituent group inwhich the nitrogen is joined extranuclearly only to nonbenzenoid carbonatoms.

Such monomers as glycidyl acr'ylate or vinyl chloroacetate can beemployed in the copolymerization. They introduce groups reactive towardammonia or amines and thus provide a means of attaching the necessarybasic amino groups to the polymer chain. Attachment of the amino groupsto the main copolymer carbon chain can be through strictly hydrocarbonstructures or through ether, ester, or amide linkages.

Particular examples of the basic amino-containing monomers include thebasic amino substituted olefins such asp-(beta-diethylaminoethyl)styrene; basic nitrogencontaining heterocyclescarrying a polymerizable ethylenically unsaturated substituent, such asthe vin'yl pyridines and the vinyl alkyl pyridines, e. g.2-vinyl-5-ethyl pyridine; esters of basic amino alcohols withunsaturated carboxylic acids such as the alkyl and cycloalkyl esters ofthe acrylic and alkacrylic acids, e.g., beta-methyl-aminoethyl acrylate,beta-diethylaminoethyl acrylate, 4-diethylamino-- cyclohex'ylmethacrylate, and beta-beta-didodecylaminoethyl acrylate; unsaturatedethers of basic amino alcohols, such as the vinyl ethers of suchalcohols, e.g., betaaminoethyl vinyl ether, and beta-diethylaminoethylvinyl ether; amides of unsaturated carboxylic acids wherein a basicamino substituent is carried on the amide nitrogen such asN-(beta-dimethylaminoethyl)-acrylamide; and polymerizable unsaturatedbasic amines such as diallylamine. The term basic amino nitrogen is usedgenerically herein to mean the primary, secondary and tertiary aminesincluding, as stated above, the basic nitrogencontaining heterocycles.

Because of their relatively greater basicity and more effective sludgesuspending and inhibiting properties, the polymerizable ethylenicallyunsaturated compounds containing a basic tertiary amino group arepreferred and those having only primary basic amino groups are leastdesirable. Particularly outstanding and readily available basic aminonitrogen-containing components are the alkyl and cycloalkyl substitutedtertiary aminoalkyl and cycloal-kyl esters of acrylic and alkacrylicacids.

The basic amino nitrogen-containing component of the copolymer must bepresent in a minor proportion by weight, corresponding to no more tha3.5% and no less than 0.1% of basic amino nitrogen based on the weightof the polymer. Above the higher level, which, for example, correspondsto about 50% by weight of amino monomer in a laurylmethacrylate/beta-diethylaminoethyl methacrylate copolymer, and at lessthan the lower level, the performance of the polymer as a sludgeinhibitor falls off rapidly. It is preferred that the basic aminonitrogen content be within the range of 0.2% to 3.0% by weight of thepolymer.

The copolymers useful in the practice of the invention can be preparedby conventional bulk, solution, or dispersion polymerization methodsinvolving known initiators, including oxygen-yielding compounds, such asbenzoyl peroxide, and azo compounds, such as alpha,alpha-azodiisobutyronitrile. Convenient solvents are highboilinghydrocarbons, particularly those similar to the hydrocarbons in whichthe copolymers are to be used, such as kerosene. The polymerizationprocess is usually carried out in an inert atmosphere such as nitrogenor carbon dioxide, at temperatures ranging from 30 C. to 150 C.,depending on the catalyst used, and generally at temperatures between 50C. and 70 C. when alpha, alpha'-azodiisobutyronitrile is used as thecatalyst. It is important to carry the copolymerization substantially tocompleteness so that little or no unpolymerized monomer remains and theproportions of each component in the final product are essentially thoseof the original monomer mixture.

'(C) Amine neutralized acid phosphates-The third component of thecompositions of this invention is an oilsoluble amine salt of an alkylacid phosphate.

The acid alkyl phosphates are obtained by reacting an alcohol withphosphoric anhydride (P From about 2 to 4 moles of a primary alkanol ormixture of such alcohols may be employed per mole of P 0 Preferred forthe present purpose are the approximately equimolar mixtures of themonoand dialkyl phosphates produced on using 3 moles of alcohol per moleof P 0 For the preparation of the acid alkyl phosphates, the alkanol isa primary alkanol, and preferably a branched primary alkanol, having 8to 18 carbon atoms. Examples are the normal alkanols derived fromcoconut kernel oils. One such fraction, available commercially consistsmainly of the n-octyl and n-decyl alcohol but contains other n-alkanolscontaining from 10 to 18 carbon atoms. Still another ranges from n-C toC with n-C predominating. Preferably the alcohol is a mixture ofbranched chain primary alkanols, such as those produced in the wellknown0x0 process from C0, H and a branched chain olefin. Examples of theseare the 0x0 octyl, decyl, tridecyl and octadecyl alcohols, all of whichare mixtures consisting predominantly of branched chain primary alkanolsobtained from propylene-butylene dimer, tripropyl ene, tetra-propyleneand penta-propylene, respectively.

The amine salts of the subject compositions are oilsoluble substitutedammonium alkyl phosphates prepared by neutralizing an acid alkylphosphate with a C to C monoamine. Most broadly, the amine can be aprimary amine containing a tert-alkyl substituent on nitrogen, or asecondary or tertiary amine containing monovalent aliphatic,cycloaliphatic, or phenyl hydrocarbyl substituents on nitrogen, or aheterocyclic amine, such as pyridine.

Preferably, the amine will be a C to C tert-al'kyl primary amine, andmost preferably the amine salt will be the salt of such an amine and theacid phosphate derived from the mixed octyl alcohols made by the 0x0process. Examples of the tert-alkyl amines used to prepare thesepreferred additives are: 1,l,3,3-tetramethylbutyl amine (tert. octylamine); the mixed tert, alkyl amine fractions having from 12 to 14carbon atoms and from 18 to 21 carbon atoms, respectively, such as thosemarketed commercially under the trade names Primene 81- and PrimeneJM-T; and tert. nonyl amine, also available commercially, consistingmainly of the C with small amounts of C and C amines and having amolecular weight range of 143 to 157.

Representative of the secondary amines and tertiary amines arediisopropylamine; di 2 ethylhexylamine; N-octenylcyclohexylamine;triethylamine; tributylamine; triisoctylamine; N,Ndiethylcyclohexylamine; dimethyl aniline and pyridine.

The amine salts suitable for use in the compositions of this inventioncan be prepared simply by neutralizing the alkyl acid phosphate with anappropriate amine to a pH of about 6-7. The mixed acidic mono anddialkyl phosphates, and their amine salts described in the examplesbelow were prepared by the following general procedures:

Anhydrous phosphoric pentoxide (P 0 was added gradually under anhydrousconditions to 3 molar equivalents of the alcohol under agitation. Theaddition of P 0 was regulated so as to maintain the reaction temperaturein the range 40 to 90 C. Good results were ordinarily obtained either at50:10" C. or at -l0 C. When the addition of P 0 was complete, thereaction mass was held at 60-70 C. for about 12 to 24 hours to completethe reaction. The course of the reaction can, if desired, be followed byconventional methods of analysis for reactants and products. In mostinstances, the acid alkyl phosphate was a viscous oil.

The amine salt was obtained by neutralizing the acid alkyl phosphate toa pH of about 7 by the addition thereto of approximately 2 moles ofamine per mole of P 0 originally employed. Conveniently, the amine,together with sufficient kerosene to produce a final solution containingabout 80% of the neutralized salt as the active ingredient, was addedgradually to the acid phosphate under agitation, and the reaction massheld at 70J -10 C. until it became completely homogeneous.

(2) Preparation of the additive compositions The three components of theantistatic composition of this invention are mixed together in a liquidhydrocarbonmiscible solvent such as xylene, toluene, benzene, hexane orkerosene and preferably heated to facilitate formation of a homogeneoussolution. They are mixed in such proportions that for one part by weightof the chromium phosphate there will be from /2 to 1 part of thenitrogen containing polymers and /2 to 16 parts of the amine neutralizedalkyl phosphate. It is preferable that the amine phosphate be addedbefore the polymer.

Since only very small amounts of the components of the composition arenecessary to be effective in preventing the accumulation of staticcharge in the hydrocarbon liquid or fuel oil, they are convenientlyadded in the form of their solvent solution. This solvent concentrateordinarily contains about 5090% by weight of the solvent. An amount ofthe solvent concentrate to be added to the liquid hydrocarbon is thatwhich will incorporate therein about 1-6 p.p.m. of the chromiumphosphate, /2--3 p.p.m. of the nitrogen containing polymer and /z-16p.p.m. of

the amine phosphate. For practical purposes, these ranges correspond toapproximately 0.3 to .2 pounds of the chromium phosphate, 0.15 to 1 lb.of the polymer and 0.15 to 4.5 lb. of the amine phosphate, per 1000barrels of liquid hydrocarbon.

(3) Conductivity measurements The effectiveness of the compositions wastested in a Maihak Conductivity Meter. Solutions of the appropriatechromium triphosphate were prepared by dissolving 0.1896 gram of thechromium triphosphate, 0.0474 gram of the nitrogen containing polymerand 0.0948 gram of the amine neutralized alkyl phosphate in 25milliliters of xylene and adding 0.1 milliliter of this solution to 1liter of jet fuel or fuel oil and evaluating the conductivity of theresulting solution with the Maihak Conductivity Meter.

The Maihak Conductivity instrument is sold by H. Maihak A.G. Hamburg,Germany, for use in the measurement of the electrical conductivity oflight oil products in ther anges of 0.500 and 0.1000 conductivity unit.A conductivity unit is equal to 1 10- mhoXmf =1 picomho m.- Theinstrument consists of a transmitter for immersion in the liquid to bechecked and an indicator unit with cable reel. Both parts are connectedvia an oilresistant cable which is wound on the cable reel.

This instrument measures the resistance of the liquid between twoelectrodes of a transmitter cell. The resistance is determined bymeasuring the current flow when applying a measuring potential of 6volts. This current is very low, a conductivity of 500 conductivityunits (C.U.) corresponds to about 6.10- A., so it is amplified by meansof an amplifier built inside the transmitter cell to a level that can beindicated on the Conductivity instrument.

The transmitter cell consists of chromium-plated brass electrodes. Bothelectrodes and cable connector are potted to one unit. The cell isimmersed in the liquid to be measured and the liquid passes throughholes below and above and circulates between the electrodes. After thetransmitter has been immersed and has come to rest, the instrument isready for measurements to be taken.

The power supply and measuring voltage to the transmitter are switchedon. The reading taken is the maximum pointer deflection immediatelyafter switching on the power.

EXAMPLE 1 To a reactor was added 239.4 grams of mixed monoanddi-isooctyl phosphate. Then 500 milliliters of anhydrous isopropanolwere added, the solution was stirred until homogeneous, and was heatedto reflux (83 C.). Next, 36.0 grams of sodium hydroxide were dissolvedin 36 grams of water and the resulting solution was added slowly to themonoand diisooctyl phosphate/isopropanol solution. The pH of the finalsolution was checked and found to be between 6-7. The solution was thenheated to reflux (83 C.) and 79.8 grams of chromic chloride (CrCl -6H O)was added. After completion of addition, the solution was stirred atreflux for 1 hour. The by-product sodium chloride (wet with isopropanoland water) was removed by filtration. The remaining solution was thensubjected to distillation followed by application of a 20-25 mm. vacuumwhile maintained at 8090 C. to remove all isopropanol and water. Twohundred and thirty four grams of chromium tri(monoand di-isooctyl)phosphate was recovered for a 93% yield.

EXAMPLE 2 To a reactor maintained with a nitrogen atmosphere was added18.2 grams of triethyl phosphate followed by the slow addition of 14.2grams of phosphorous pentoxide. The reaction solution was kept at 75-80C. during the addition. After all of the phosphorous pentoxide wasadded, the reaction solution was held at 75-80" C. for an additional 2hours. The solution was then cooled to 60 C. and 39.1 grams ofZ-ethylhexanol were added and the reaction mass was stirred for about 20hours at C. to obtain ethyl 2-ethylhexyl phosphate. The chr0- mium saltof the dialkyl phosphate was prepared as in Example 1. Sixty-one andthree tenths grams of chromium tri-(ethyl-Z-ethylhexyl phosphate) wereobtained for an 86% yield.

By following this same procedure, 59.4 grams of chromium tri-(ethyl,isooctylphosphate), (83% yield) and 61.6 grams of chromium tri-(ethyl,n-octylphosphate), (86.4% yield) were obtained.

EXAMPLE 3 To a reactor were added 100 milliliters of carbontetrachloride and 30.64 grams of di-2-ethylhexyl phosphite. The solutionwas cooled to 0.5 C. and chlorine was bubbled through the solution at amoderate rate. After the solution became yellow in color (indicating anexcess of chlorine) the introduction of chlorine was stopped and thesolution stirred at 05 C. for /2 hour. The excess chlorine was thenremoved by purging the solution with nitrogen. The carbon tetra-chloridewas then removed to give 34.2 grams of di-Z-ethylhexylphosphorochloridate which was immediately converted into thedi-2-ethylhexyl phosphate by the following procedure.

To a flask charged with 250 milliliters of water and 7.9 grams ofpyridine was added dropwise 34.1 grams of di-Z-ethylhexylphosphoro-chloridate while the solution was kept at about 30 C. Aftercompletion of the addition, the temperature of the solution wasincreased to C. and held for about 3 hours. The solution was then cooledand extracted with hexane and diethyl ether. The hexane/ether layerswere dried with sodium sulfate. The hexane/ether was then removed togive 24.9 grams of di-Z-ethylhexyl phosphate, for a 77% yield.

EXAMPLE 4 To the 234.0 grams of chromium tri(monoand diisooctylphosphate) obtained in Example 1, there was added 468 grams of kerosene.This heterogeneous solution was stirred at 80 C. for 1 hour while mostof the chromium alkyl phosphate was dissolved. To this solution wasadded 117.0 grams of the Primene 81-R salt of mixed monoand diisooctylacid phosphate, followed by stirring at 80 C. for /2 hour. 117.0 gramsof a terpolymer consisting of octadecenyl methacrylate, styrene andfi-diethylaminoethyl methacrylate, 50/40/10, was then added and theresulting solution stirred at 80 C. for 1 hour. The final solution wasallowed to cool and filtered to remove any undissolved material.

The initial conductivity tests are reported below in Table I and TableI-A.

TABLE L-CONDUO'IIVITY IN HYDROOARBON LIQUIDS Concentration, Conducp.p.m.in tivity J P-4 picomho Additive fuel a m.-

None 0-10 Chromium tri(di-Z-ethylhexylphosphate) 1 Primene 81-R 1 saltof monoand diisooctyl acid phosphate 12 10 Chromiumtri(di-Z-ethylhexylphosphate) 1 Primene 81-12." salt of monoanddiisooctyl acid phosphate 0. 5 Polymer A 0. 5 Chromium tri(monoanddiisooctyl phosphate) 1 Primene 81-R salt of monoand diisooctyl acidphosphate V 0. 5 450i50 Polymer A 0.5 Primene 81-12 salt of monoanddiisooctyl acid phosphate 12 Polymer A 12 40 Chroimum tri(methyl,isooctyl phosphate). 1 "Primene BI-R salt of monoand diisooctyl acidphosphate 0.5 Polymer A. 7 0. 5 300i50 Chromium tri(monoand diphenylphosphate)- 1 Primene 81-R" salt of monoand diisooctyl acid phosphate0.5 01 A 0.5 70:1;20

Primene 81-13. salt of monoand diisooctyl phosphate TABLE 1--'ContinuedConcentration, Conducp.p.m. in tivity J P-4 picomho Additive fuel 8 XmrPolymer A 0. 5 50:l:20 Chromium t ri(monoand diisooctyl phosphate). 1n-Propylamine salt of monoand diisooctyl phosphate 0. 4 Polymer A 0. 5280 Chromium tri(monoand diisooctyl phosphate). 1 Ethanolamme salt ofmonoand diisooctyl phosphate 0. 4 Polymer A 0. 5 500 Chromium tri(monoand diisooctyl phosphate). 1 Dimethylcyclohexylamine salt ofmonoand diisooctyl phosphate Polymer A Chromium tri(monoand diisooctylphosp e) Di-Z-ethylhexylamine salt of monoand diisooctyl phosphatePolymer A Chromium tri(monoand diisooctyl phosphate). n-Decylamine saltof monoand diisooctyl Polymer A Chromium tri(monoand diisooctylphosphate). Aniline salt of monoand diisooctyl phosphate.. Polymer AChromium tri(monoand diisooctyl phosphate). 2-Ethylhexylamine salt ofmonoand ditridecylphosphate Polymer A Chromium tri(monoand diisooctylphosphate). "Primene 8l-R salt of monoand diisooctyl TABLE IL-WATER WASHTEST Conductivity picomho m.-

Before After wash wash Concentration p.p.m. in Additive JP-4 fuelChromium tri(mon0- and diisooctyl phosphate) "Primene 81-11" salt of mphosphate). Primene 81R" salt of isooctyl phosphate. Polymer C Chromiumtri(monoand diisooctyl phosphate) Polymer C phos hate 16 Polym r A 0. 5500400 TABLE III Chromium tri(monoand diisooctyl phosphate). 1 Primene81-12." salt of monoand diisooctyl Amine of 1110110 and diisooctylphosphate 1 Phosphate (rggly'mer A. ".n n u nn n i 450-550 ggzf g W ightG 1 romium tri monoan 'isooc y p osp ate e e a- Primene 81-R salt ofmonoand diisooctyl 801mm Percent Amine Percent fi m Iihosp 1;? "B116 185 Ye s. P0 ymer u 2 81 Primene 81-R 4 N l Primene 81R is a mixture oftertiary alkyl amines containing from 12 3 31 Z HiNH 4 No. to 14 carbonatoms. 4 81 Triethylamme 4 No. 2 PolymerAis 50/40/10 wt. percentoctadecenyl methacrylate/styrene/B- 5 31 i y ye ohexy emi 4 No.diethylaminoethyl methacrylate. 5 81 Y Y e-- 4 No. 8 J P-4 fuel had thefollowing inspection data: APT gravity, 46; Aro- 31 e y e 4 No. maticmax., 25 volume percent; Olefin content, 5 volume percent; Boiling 81 yp4 No. range, 50% at 370 F., 90% at 470 F. 81 Amlme 4 No. 4 Polymer B is95/5 wt. percent 2-ethylhexyl acrylate/diethylamino- 10 81 y y mme Sell;4 No. ethyl vinyl ether. m0n0- and d1tndecyl phosphate.

TABLE I-A Conductivity, average picomhoXm.-

Concen- I In tration, In fuel In fuel rubber In mineral Additive p.p.m.011 D oil E solvent I heptane spirits 1 Chromium tri(monoand diisooctylphosphate). 1 "Primene 81-R salt of monoand diisooctyl phosphate. 0. 5Polymer A 0. 5 90=i=10 120=|=10 -1,o00 350530 525g Chromium tri (monoanddiisooctyl phosphate)- 6 "Primene 8l-R salt of monoand diisooctylphosphate-.. 3 Polymer A 3 470=l=20 600=|=20 1 Commercially availableNo. 2 fuel oil.

2 Petroleum distillate used in making rubber cements and in tiremanufacture, volatility similar to gasoline (boiling range 150-3 F) Inorder to demonstrate the ability of the additive compositions of theinvention to remain in the oil phase, they were subjected to a stringentwash test described below.

Effect of washing with water Procedure-To one liter of JP-4 jet fuel wasadded ,ul of a stock solution containing one of the antistatic additivecompositions in kerosene or xylene. This resulted in the Chromium tri(alkyl phosphate) being added at 1 p.p.m. to the jet fuel, the aminephosphate and nitrogen containing polymer being present at /2 p.p.m. Theconductivity of the resulting solution was then measured after thesolution had been stored for several days in metal cans so that anequilibrated value could be obtained.

The one liter jet fuel solution was then thoroughly mixed with 100 ml.of water for 5 minutes. The water was then allowed to separateand wasremoved. The conductivity of the jet fuel solution was then determinedagain with the Maihak Conductivity Meter.

00 i Petroleum distillate used as thinner in paints and varnishes with aboiling range of 200-300 F.

What is claimed is: 1. A composition for increasing the conductivity ofhydrocarbon liquids consisting essentially of (1) one part by weight ofa trivalent chromium salt of (a) an alkyl phosphate, said salt havingthe formula wherein R and R can be the same or different, and

R is alkyl of 1 to 16 carbon atoms, alkylphenyl wherein the alkylcontains 1 to 16 carbon atoms, or phenyl, and R is alkyl of 3 to 16carbon atoms, alkylphenyl wherein the alkyl contains 1 to 16 carbonatoms, or phenyl; or

1 1 (b) a mixture of (i) 60 to 40 mol percent of a monohydrocarbondihydrogen phosphate, and (ii) 40 to 60 mol percent of a dihydrocarbonmonohydrogen phosphate, wherein the hydrocarbon is alkyl of 4 to 16carbon atoms, alkylphenyl wherein the alkyl contains 1 to 16 carbonatoms, or phenyl (2) from .5 to 1 part by weight of an oil solublecopolymer wherein (a) from about 50 to about 95% by weight of thepolymer is units from a long-chain ester of an unsaturated carboxylicacid which contains from 8 to 18 carbon atoms in an aliphatichydrocarbon chain which is not part of the polymer chain; (b) from aboutto about 10% by weight of the polymer is units from unsaturated ethersof basic amino alcohol, or esters of basic amino alcohols withunsaturated carboxylic acids, wherein the basic amino nitrogen is notitself part of the polymer chain; (c) from 0 to about 45% by weight ofthe polymer is units from styrene; and (d) each of the monomers, priorto polymerization, contains a carbon-carbon double bond capable ofparticipation in free radical initiated addition copolymerization; saidcopolymer having an inherent viscosity of between 0.1 and 3.0 at 1%weight-volume concentration in benzene at 25 C. and containing from 0.1to 3.5 weight percent of basic amino nitrogen; and (3) from .5 to 16parts by weight of an oil soluble salt of (a) a 2 to 24 carbon atommonoamine selected from among (i) tertiary alkyl primary amines; (ii)secondary amines having 2 monovalent 12 saturated hydrocarbon radicalsubstituents; and (iii) tertiary amines having 3 monovalent saturatedhydrocarbon radical substituents; and (b) mixed monoalkyl acidphosphates and dialkyl acid phosphates wherein the alkyl groups contain8 to 18 carbon atoms.

2. A composition of claim 1 wherein the oil soluble salt (3) is the saltof an 8 to 21 carbon tertiary alkyl primary amine, and an acid phosphatein which the alkyl groups are branched chain primary alkyl groups.

3. A solution of a composition of claim 1 in a hydrocarbon-misciblesolvent, said solution containing about to percent 'by weight of saidsolvent and about 10 to 40 percent by weight of the composition of claim1.

4. A liquid hydrocarbon composition comprising a major portion of aliquid hydrocarbon and an amount suflicient to increase the conductivityof said liquid hydrocarbon of a composition of claim 1.

References Cited UNITED STATES PATENTS 3,126,260 3/ 1964 Van der Minne4462 3,210,169 10/1965 Van der Minne 44-'-62 3,336,124 8/1967 Dunworth4462 3,012,969 12/1961 Van der Minne 4470 3,084,035 4/1963 Rogers et a1.44-68 3,397,971 8/1968 Van der Minne 4468 3,013,868 12/1961 Skei et a1.44-62 2,888,340 5/1959 Winnick 4462 DANIEL E. WYMAN, Primary Examiner Y.H. SMITH, Assistant Examiner US. Cl. X.R. 4468, 72, Dig. 4

